# A107761 (b-file synthesized from sequence entry) 1 1 2 2 3 6 4 24 5 72 6 480 7 3600 8 9600 9 108000 10 1270080 11 4795200 12 74088000 13 768539520 14 4759413120 15 94182359040 16 1893397524480 17 11353661706240 18 122634632171520 19 3104438623534080 20 23063946114908160 21 664424069072117760